Method for treating waste gases from plants for pig iron production

Abstract

A method and a system for treating waste gases (4) from plants (32, 33) for pig iron production, wherein a first sub-stream (51) of the waste gas is subjected to an at least partial conversion of CO into CO2 after the addition of water and / or water vapor (10) and the waste gas (4) is then subjected to CO2 capture. To be able to set a variable H2 / CO ratio in the waste gas, a further sub-stream (52) of the waste gas is not subjected to a conversion of CO into CO2, but is subjected to CO2 capture separately from the first sub-stream (51).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application is a 35 U.S.C. §§371 national phase conversion of PCT / EP2012 / 066319, filed Aug. 22, 2012, which claims priority of Austrian Application No. A1245 / 2011, filed Aug. 31, 2011, the contents of which are incorporated by reference herein. The PCT International Application was published in the German language.FIELD OF THE INVENTION[0002]The invention relates to a method and a device for treating waste gases from plants for pig iron production, wherein a first sub-stream of the waste gas is subjected to an at least partial conversion of CO into CO2 after the addition of water and / or water vapor and the waste gas is then subjected to CO2 capture.PRIOR ART[0003]There are essentially two known common methods used for the production of pig iron, which also includes the production of pig iron-like products: the blast furnace method and the smelting-reduction method.[0004]In the blast furnace method, firstly pig iron is made fro...

AI Technical Summary

Benefits of technology

[0074]the reducing reactors (blast furnace, fluidized reactors, reduction shafts) can be dimensioned smaller because the reducing gas is better utilized due to the high hydrogen content and has a lower density,

[0076]a reduction in the risk of “metal dusting” corrosion due to the greater H2 / CO ratio is enabled,the following advantages can be achieved with the method and the device according to the invention:

Problems solved by technology

The disadvantages of the blast furnace are the requirements placed on the input materials and the high output of carbon dioxide.

The CO2 output represents a serious environmental burden.

This has the disadvantage that large quantities of steam are required due to the necessary steam excess of approximately 300 t / h in the case of a COREX® system.

The large hydrogen content leads to a limitation of the pig iron production and also necessitates high reducing gas temperatures.